1 Field of the Invention
The present invention relates to an electrolytic coloring method for chromium alloy, and specifically relates to an electrolytic coloring method for chromium alloy which colors the surface of chromium alloy, for example, stainless steel by applying electrolytic treatments thereto.
2 Description of the Prior Art
The conventional electrolytic coloring method for chromium alloy is disclosed, for example, in the Japanese Patent Publication No 32621/1977. This method is such that stainless steel as a chromium alloy is immersed in an aqueous solution containing chromic acid and sulfuric acid, and the stainless steel undergoes an anode electrolytic treatment to form a porous oxide film on the stainless steel, and thereby the surface of the stainless steel is colored.
Also, this inventor proposed an electrolytic coloring method for chromium alloy which can adjust the color tone of an oxide film to be formed based on the current density and the treating time of the anode electrolytic treatment in such a conventional electrolytic coloring method for chromium alloy.
In the conventional electrolytic coloring method and in the electrolytic coloring method proposed by this inventor, with the lapse of treating time of the anode electrolytic treatment, the color tone of the oxide film to be formed varies sharply, and therefore adjustment of the color tone is difficult and reproducibility of the color tone is worse.